Late to the thread. I owned both the 35d and 35i. For me the 35i is the easy winner and I'm currently driving a 2013.

With the price of diesel where it is, there is little or no advantage is fuel costs. The 35i is faster than the 35d 0 - 60 which is what I cared about more. I also prefer the 8 speed automatic.

Plus the 35i doesn't make you mess around with urea, deal with the occasional burn off smell, or enjoy dirty gas pumps.

I'm not knocking those who own the 35d. Just my opinions.